PROJECT SUMMARY Recent research provides novel evidence that childhood economic disadvantage undermines health among older adults. Despite valuable contributions, most US-based research on this provocative theme has relied on retrospective recollections of childhood resources from decades in the past. Even with prospective data, this literature largely uses measures of childhood economic resources that do not rise to leading international standards. We improve upon past research in critical ways by more fully incorporating leading international standards in income measurement into the study of health. We will use the Panel Study of Income Dynamics (PSID), a large, nationally representative study that prospectively measures childhood economic resources as well as a variety of health outcomes in mature adulthood. We capitalize on a pivotal strength of the PSID when merged with the Cross-National Equivalent File (CNEF): comprehensive and higher quality prospective measures of childhood income inclusive of taxes and transfers. We will strategically exploit the most recent waves of the PSID-CNEF to include a larger sample of children from the 1970s and 1980s who have reached ages 40-63 by 2017. Our project has three specific aims. First, we will provide the most rigorous assessment to date of the relationship between childhood economic resources and mature adult health outcomes. More precisely, our innovations will demonstrate (a) potential nonlinearities and critical thresholds in the income- health relationship; (b) which measures of mature adult health are most influenced by childhood income; and (c) which elements of economic resources are most crucial to mature adult health. Second, we will assess whether relative or absolute childhood income is most important to mature adult health. Third, we will investigate the role of adult socio-economic attainment and adult health behaviors as mediating pathways. Finally, we will build a public good infrastructure of code for replication and to encourage better measurement of childhood economic resources in studies using the same or other datasets. By incorporating leading standards in income measurement, and utilizing higher quality data on prospectively measured childhood income and a wide variety of health outcomes among older adults, this project has the potential to make novel and salient contributions. We aim to improve understanding of the relationship between childhood economic resources and mature adult health. More generally, we will contribute to several fields in the social science of health, healthy aging, and health disparities. By making these contributions, we will advance these fields? already valuable knowledge for public policy. Specifically, our research can inform more effective targeting of interventions ? at which points in the childhood income distribution and through which mediating pathways ? to improve mature adult health. Our research can also guide health practitioners with more reliable and predictive early warning signals for specific health problems in mature adulthood.